1. Field of the Invention
This invention relates to fibers of poly(p-phenylene terephthalamide) (PPD-T) which exhibit textile properties, including an elongation to break of at least 7%. It, also, relates to the air-gap spinning process for making such fibers.
2. Description of the Prior Art
U.S. Pat. No. 3,671,542, issued Jun. 20, 1972 on the application of Kwolek, discloses a wet-spinning process for making para-aramid fibers by wet-spinning an anisotropic dope into a cold coagulation bath. Example 72 in that patent specifically discloses a high denier, low modulus, relatively low tenacity and high elongation PPD-T fiber; spun from a 10% anisotropic solution made by mixing low inherent viscosity polymer and 100.4% sulfuric acid to make a dope to be spun into a 4 C coagulation bath.
U.S. Pat. No. 3,767,756, issued Oct. 23, 1973 on the application of Blades, discloses a process for air-gap spinning PPD-T fibers.
U.S. Pat. No. 4,898,704 issued Feb. 6, 1990, on the application of Luckey, discloses a device and method for coagulating a warp of filaments from a linear spinneret by delivering a jetted sheet of coagulating liquid equally and uniformly to each side of the warp.